The writer's experience very much mirrors my experience with your's and Pete's products although I only have a Digibuss. I do not have a Uber...... yet (just don't tell that to my wife )

However I do have to take exception with one section of that review and that is when he talks about AC polarity. We have talked at length in other threads about the dangers of disconnecting safety grounds and doing hot/neutral swaps. Polarized plugs and three wire connections are specified int the NEC and UL standards for a reason and people need to understand that bypassing those safety features puts not only your equipment and your home but also the safety and even the lives of yourself and your family at risk. I don't think many of the people who play around with plugs and polariity are aware of the risks that they are taking. I don't care how good a modification makes my stereo sound, in my mind NOTHING is worth even the slightest risk of putting my loved ones in jeopardy.

What is interesting about AC plug wiring from that discussion is when you only have two wire non-polarized plugs. There is one orientation of the plug that gives the lowest AC leakage to the chassis. A lot of older audio equipment had those.

In my testing it has always led to the lowest AC hum from the equipment.

I have one phono preamp that uses a toroidal AC transformer and an IEC 3-wire connection. It hummed when I bought it used. Tracked it down to the primary of the transformer being wired backwards. Checked and the chassis leakage was lower and hum gone after rewiring the primary.

Class 2 connections on audio gear can be a problem, not only from an iffy safety standpoint, but from a sonics viewpoint.

Point in example is the unpolarized AC power cable that connects a Mac mini to the wall. The mini is essentially double insulated so shocks are not really an issue. What is extremely important is the polarity ofthat plug has a big influence on SQ. One orientation sounds kind of value and flat. Turn the plug over and everything gets better. Bass, timbre of instruments and most importantly imaging and soundstage are much better.

With SMPS plug orientation is a big deal. If there is a SMPS in the system that supplies gear try both orientation to hear which sounds best. Then report your findings here for all to see.

OK?

Maybe We should split this off into a different thread. Whatcha think? Nick?

Logged

"A man with an experience is never at the mercy of a man with an argument." - Hilmar von Campe

Dave you are right and I should clarify my rant. If a particular unit come with a non polarized plug then the design is not polarity sensitive and by all means go ahead and experiment. But if the AC cord for a unit is polarized, be it with a three prong or a wide blade plug then the designer is trying to force you to power it with a certain polarity for a reason And most often that reason is safety.

And safety should always take priority over sound quality.

The bottom line here is if a plug allows you to change its orientation with no modifications at all then it is safe to do so and have fun.

But if you have to make any changes at all to the physical changes at all to make the polarity change happen whether they be modifications to the plug itself, adding some kind of inline adapter or doing any kid of wiring change to the connections in the power cord or the unit it is connected to, this is probably not something that you should be doing.

Guys I'm sorry if I sound like I am up on a soap box here, but I spent too many years designing industrial power plants and back-up systems to not have anything but the greatest respect to dangers that electricity brings into our homes. I have seen first hand the destructive force that even a "small electrical supply (like a 24 volt DC battery plant) can unleash when safety protocols are not followed to the letter and an installer takes even a "minor" shortcut. People today have become blind to the dangers of electricity precisely because of the safety standards that the National Electric Code put into building wiring rules and the testing standards that organizations like Underwriters Labs have forced manufacturers to build into their products.

There is a reason that building inspectors need to certify the electrical wiring before the sheetrock goes up in a new house. And that is because contractors that try to get away with doing installations that are not up to code to save themselves a few bucks result in houses that burn to the ground.

Safety standards are only effective if they are followed 100% of the time and this includes not only when an installation is done or product is manufactured but also every time the product is used throughout its lifetime.

Everything about electricity and electrical products needs to be safety first and functionality second.

We can all put our heads in the sand and say the odds of anything going wrong are tiny and it will never happen to me, but do you want to be that guy whose wife and kids were killed in an electrical fire who says to his friends "Yeah, the family is all dead, but damn you should have heard how much bigger the soundstage was when I flipped that plug."

Guys I'm sorry if I sound like I am up on a soap box here, but I spent too many years designing industrial power plants and back-up systems to not have anything but the greatest respect to dangers that electricity brings into our homes. I have seen first hand the destructive force that even a "small electrical supply (like a 24 volt DC battery plant) can unleash when safety protocols are not followed to the letter and an installer takes even a "minor" shortcut. People today have become blind to the dangers of electricity precisely because of the safety standards that the National Electric Code put into building wiring rules and the testing standards that organizations like Underwriters Labs have forced manufacturers to build into their products.

There is a reason that building inspectors need to certify the electrical wiring before the sheetrock goes up in a new house. And that is because contractors that try to get away with doing installations that are not up to code to save themselves a few bucks result in houses that burn to the ground.

Safety standards are only effective if they are followed 100% of the time and this includes not only when an installation is done or product is manufactured but also every time the product is used throughout its lifetime.

Everything about electricity and electrical products needs to be safety first and functionality second.

We can all put our heads in the sand and say the odds of anything going wrong are tiny and it will never happen to me, but do you want to be that guy whose wife and kids were killed in an electrical fire who says to his friends "Yeah, the family is all dead, but damn you should have heard how much bigger the soundstage was when I flipped that plug."

I know I sure don't.

Tom, you're 100% correct! I know some "Audiophools" who defeat Safety Grounds and I have no idea what the dire consequences could be...

Yes, sirs! Failure to follow electrical protocols is just stupid when one has no idea what is the safe way to proceed.

Two personal cases here:

When I was young I worked in a music store (surprise ) and one summer the air handlers in the mall shut down. We got some large floor fans to circulate air. I went to move them while they were running. I grabbed one and went to get the other one. As I grabbed the second one I became immediately aware that one of the plugs had been replaced without following color code with a non polarized plug. I couldnt let go. My boss saw what was happening and quickly unplugged one. I think he saved my life that night.

I worked in implant at Philips Semiconductor until they pulled up stakes in America. Implanters back then pulled vacuums in the -8 torr range, developed huge magnetic fields, produced ionizing radiation, ran on poisonous gasses and voltages up to 1,000,000 V. To top this off there was the source. An implanter is essentially a single car garage. The source arc is the filament. Variable voltages from about2 - 25VDC at currents up to 250A.

I was on the ERT (emergency response team) and I saw the results of a moron (rest his soul) that did not follow strict lock out/tag out (LOTO) protocols. It is something I will never forget.

« Last Edit: May 18, 2019, 10:15:57 AM by P.I. »

Logged

"A man with an experience is never at the mercy of a man with an argument." - Hilmar von Campe

For safety purposes the safety ground should be big enough to carry the full capacity if the circuit. Unless it can handle the fault current when a phase to chassis fault occurs, this wire will most probably overheat and possibly even fuse.

The National Electric code recommends on Table 250.122 that for a circuit connected to a breaker of up to 30 amps the size of the safety ground wires should be the same as the current carrying conductors for a given breaker size. So unless the gauge of your IC wire is equal to or greater than that of the power cored connecting the unit you are running a risk by relying on the IC to provide a a safety path to ground.

And this of course assumes that the return of the IC circuit is designed to be at earth potential and it is not a floating ground circuit in which case the IC cable would not have a earth path in the first place.

When I was young I worked in a music store (surprise ) and one summer the air handlers in the mall shut down. We got some large floor fans to circulate air. I went to move them while they were running. I grabbed one and went to get the other one. As I grabbed the second one I became immediately aware that one of the plugs had been replaced without following color code with a non polarized plug. I couldnt let go. My boss saw what was happening and quickly unplugged one. I think he saved my life that night.

Which is essentially the same thing as using some kind of cheat to force a polarity change on a polarized plug.

When I was young I worked in a music store (surprise ) and one summer the air handlers in the mall shut down. We got some large floor fans to circulate air. I went to move them while they were running. I grabbed one and went to get the other one. As I grabbed the second one I became immediately aware that one of the plugs had been replaced without following color code with a non polarized plug. I couldnt let go. My boss saw what was happening and quickly unplugged one. I think he saved my life that night.

Which is essentially the same thing as using some kind of cheat to force a polarity change on a polarized plug.

I rest my case.

Logged

"A man with an experience is never at the mercy of a man with an argument." - Hilmar von Campe